Controlled substances such as opioids have the potential to be misused and abused and must be disposed of properly to avoid diversion to a drug addict. Drugs that are disposed of in household trash or flushed away may leach into landfills or enter the water supply, where they can do environmental harm.
Properly disposing of controlled substances is difficult for consumers. Drug take back programs exist, but are time consuming and inconvenient for many people. Even if disposed of in the trash, a drug can sometimes be retrieved and misused or abused. For example, packaging that encapsulates a pharmaceutical product to prevent leaching in a landfill can still be reopened by a person to access the drug. Some pharmacies have begun a mail-in program; however, these programs can be costly and inconvenient for consumers, which limits their use.
The inclusion of detection agents and/or inactivation agents in disposal packaging is known, in which the agent is released when the agent or the dosage form is misused. Such agents include indelible dyes, opioid receptors that bind the residual opioid into an insoluble ligand-receptor complex, opioid receptor antagonists, physical sequestering agents, or non-opioids with distressing or dysphoric properties. However, many inactivation agents are specific for a particular drug compound and are not effective when used with other drugs. Disposal may compound environmental discharge issues by the addition of more medically active compounds into landfills or the water supply. The detection and/or inactivating agents are released only when the article is misused, and therefore are not activated when the pharmaceutical is used properly and discarded.
Another known approach is the use of activated carbon to which pharmaceutical molecules and toxins can bind through intermolecular forces. Pharmaceuticals that are bound to the activated carbon are no longer mobile or physiologically active. However, this is an equilibrium process and is dependent on contact with the materials. Activated carbon absorbs a variety of organics and simple physical adsorption is not deactivation. A major drawback of adsorbents such as activated carbon is that they can easily be saturated due to surface fouling, non-specific adsorption, and overwhelming the adsorption capacity by inert formulation and insoluble ingredients, by addition of too much medication, or by inadequate mixing, resulting in poor or incomplete adsorption of the active pharmaceutical agent. For example, a commercial kit containing a limited amount of carbon exposed to hundreds of tablets could not reliably deactivate specific active ingredients. Also, by altering conditions such as pH, or by using selective solvent systems, active drugs could be desorbed by skilled practitioners. Kits in which activated carbon is included can be inconvenient to use, or may not be used correctly and yet still add to the mass in landfills.